1. Field of the Invention
The present invention is generally related to processes and systems for recovering a liquid natural gas (“LNG”) from a hydrocarbon-containing gas. More particularly, the present invention is generally related to processes and systems for removing nitrogen from a hydrocarbon-containing gas and producing a LNG stream.
2. Description of the Related Art
Due to the increased demand for methane, unconventional gas sources have been increasingly utilized as feed streams to produce LNG. However, such unconventional gas sources can contain high concentrations of nitrogen, which can cause several operational problems as the gases are subjected to liquefaction in a LNG facility. For example, the presence of high concentrations of nitrogen in the gas feed streams can prevent the methane from fully condensing and can negatively affect the quality of the produced LNG stream.
Due to the commercial value of methane, it can be desirable in some cases to remove at least a portion of the nitrogen from the gas feed streams during processing. However, some conventional processes for removing nitrogen can only be commercially viable for certain types of feed streams depending on their nitrogen concentration. Furthermore, many of the conventional nitrogen removal processes are not particularly suited for removing smaller concentrations of nitrogen from gas feed streams during processing. Moreover, it can be difficult to regulate temperature and other operating conditions during many of these conventional nitrogen removal processes, which can negatively impact the ability to effectively remove nitrogen from the resulting LNG stream and to produce a specification LNG product.
Therefore, there is a need for processes and systems that can more effectively remove lower concentrations of nitrogen from hydrocarbon-containing gases when producing LNG.